Masanori was the artist name (go) of Akamatsu Jiro, daimyo of Shirahata in Harima and a retainer of the Ashikaga. He was descended from Minamoto Morofusa of the Murakami-Genji. He made blades for himself in his leisure time, having as his teachers employees of the Akamatsu Family, the illustrious Bizen swordsmiths, Katsumitsu and Munemitsu. As seen in the inscription on this example, most of his blades were made as gifts for men of influence. See Daitokuji bunsho for more specific geneologies.

Only fourteen of his blades (including this example) are known to exist. They include dates ranging from Bunmei 14 (1482) to Mei-o 3 (1494).

Kamiyama was a retainer of Iio Kiyofusa, who was bugyo (shogunal viceroy) of the bakufu. Called Miyoshi Kazutsure, Kamiyama is cited in Seisaku daisojo-ki as seeking the position of daikan (Ashikaga governor of a feudal fief in the absence of the titular owners) of Obu no sho, Bizen Province, as a sosha of Urakami Norimune. In that position, he was able to serve as mediator between Masanori and the Osafune swordsmiths, Ukyo-no-Suke Katsumitsu and Sakyo-no-Suke Munemitsu. Kamiyama was able to successfully negotiate the employment of these two smiths for the private use of the Akamatsu family, earning him the gratitude of Masanori.